This invention relates to I/O apparatus for computing devices and, more particularly, to a low power optical transceiver that can be simply and inexpensively incorporated into a portable computing device such as a solar or battery-powered calculator or be coupled to a computer.
Computing devices such as calculators and computers conventionally communicate with other devices through a cable that physically connects to an I/0 port on each device. The integrity of the communication may be degraded, however, by physical wires within the cable. The wires produce electromagnetic radiated noise and provide a path for destructive ESD (electrostatic discharge).
Communicating information optically avoids the drawbacks associated with wire connections. IR (infrared) transmitters are currently employed in the portable computing environment such as in the battery-powered Hewlett-Packard 28S calculator. The IR transmitter within that calculator draws so little power that the calculator, with only battery power, can transmit information such as data and instructions to a printer equipped with an IR receiver.
To date, however, it has been impractical to include a corresponding IR receiver within the portable computing device for receiving data. Prior IR receivers are too large, costly, and power hungry to be adapted for use in a portable computing device. Adding an IR receiver would enable the portable device to receive information more accurately and quickly than is possible through plug-in modules, cards or by manual entry.